Typical Application

Description

The LTC3780 is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The constant frequency current mode architecture allows a phase-lockable frequency of up to 400kHz. With a wide 4V to 30V (36V maximum) input and output range and seamless transfers between operating modes, the LTC3780 is ideal for automotive, telecom and battery-powered systems.

The operating mode of the controller is determined through the FCB pin. For boost operation, the FCB mode pin can select among Burst Mode® operation, Discontinuous mode and Forced Continuous mode. During buck operation, the FCB mode pin can select among Skip-Cycle mode, Discontinuous mode and Forced Continuous mode. Burst Mode operation and Skip-Cycle mode provide high efficiency operation at light loads while forced continuous mode and discontinuous mode operate at a constant frequency.

Fault protection is provided by an output overvoltage comparator and internal foldback current limiting. A Power Good output pin indicates when the output is within 7.5% of its designed set point.

Protected by U.S. Patents, including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on current mode architecture and protection

Order Info

Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.

* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

Step 1: If you have not installed LTspice on this computer, download and install LTspice

Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation

Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

To open the project file for this circuit:

Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD

Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file

Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu

Design tools for the following parts are available in LTpowerCAD:LTC3780